Child abuse is a major social and public health concern that adversely affects the physical, psychological, and social well-being of children. Despite legal safeguards and child protection initiatives in India, children continue to experience various forms of abuse and neglect. The present study aimed to examine the prevalence of child abuse and assess its impact on the physical and mental health of children in selected blocks of Bhagalpur District, Bihar. A descriptive and analytical cross-sectional research design was adopted. Primary data were collected from 100 children aged 10–18 years from the blocks of Bihpur, Gopalpur, Ismailpur, Kharik, Narayanpur, and Naugachhia using a structured questionnaire and interview schedule through multi-stage random sampling. The findings revealed that emotional abuse (41%) was the most prevalent form of abuse, followed by physical abuse (32%), neglect (18%), and sexual abuse (9%). Common physical health problems among abused children included injuries (29%), nutritional deficiencies (26%), frequent illness (24%), and sleep disturbances (21%). Anxiety (31%), fear (27%), and depression (19%) emerged as the major mental health concerns. Chi-square analysis indicated a significant association between child abuse and physical health status (χ² = 10.95, p = 0.004) as well as mental health status (χ² = 11.68, p = 0.003). Furthermore, Pearson's correlation analysis revealed a significant positive relationship between child abuse and overall health status (r = 0.624, p < 0.001). The study concludes that child abuse significantly impairs both the physical and mental well-being of children. Strengthening child protection mechanisms, promoting parental awareness, expanding counselling services, and implementing community-based interventions are essential to prevent abuse and safeguard children's health and development.